1. Field of the Invention
The present invention relates to digital images and more particularly to a deinterlacing apparatus of digital image data by obtaining motion information and executing interpolations according to the motion information.
2. Discussion of Related Art
Generally, a picture of a digital TV may be displayed on a monitor by interlaced scanning or progressive scanning. Some display monitors require one type of scanning pattern while the image is received in the other type of scanning pattern. Therefore, a deinterlacing apparatus converts an interlaced field to a non-interlaced field (or progressive frame) data by filling pixel values of omitted field lines in the interlaced field.
Particularly, a digital TV supports a display of progressive frame data. As a result, if an interlaced field is received, the data must be converted into the progressive frame data. Typical methods used for converting the interlaced field into the progressive frame are an inter-field interpolation method which inserts data from a previous field between current field line data, without motion compensation, and a line doubling method which repeatedly uses field line data of a current field. There are other methods such as an intra-field interpolation method which uses a linear line interpolation of the current field.
FIG. 1A shows the line doubling method, FIG. 1B shows the inter-field interpolation method, and FIG. 1C shows the intra-field interpolation method. Such interpolation methods can be constructed by simple hardware, but may cause degradation to the image. Namely, in the line doubling method, the image quality of displayed video would generally be degraded after an interpolation. In the inter-field interpolation method without the motion compensation, the image quality of video portions with motion may considerably be degraded after an interpolation. In contrast, the image quality of video portions without motion may be degraded after interpolation by the intra-field interpolation method.
Accordingly, a method of detecting a motion and converting the interlaced field to a progressive frame has been proposed by Bernard in U.S. Pat. No. 5,027,201 and by Faroudja in U.S. Pat. No. 5,159,451. Although these methods improve the video quality after interpolation, a complicated hardware including a plurality of memories and a complicated processing are required. As a result, the overall cost of manufacturing a deinterlacing apparatus would increase, thereby increasing the cost of a digital TV.
Accordingly, an object of the present invention is to solve at least the problems and disadvantages of the related art.
An object of the present invention is to provide an efficient deinterlacing method and apparatus.
Another object of the present intention is to provide a deinterlacing method and apparatus for digital image data, which is capable of improving a quality of the displayed video.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purposes of the invention, as embodied and broadly described herein, a deinterlacing apparatus includes a BD and BPPD detecting unit for calculating a brightness profile pattern difference and a brightness difference between a current field and a previous field data; a BD and BPPD combiner for respectively limiting the obtained BD and the BPPD by a threshold value, mapping the BD and BPPD to preset levels, and deciding an extent of motion present according to its magnitude; a median filter for eliminating a noise component of the extent of motion value output by the BD and BPPD combiner, and grouping portions with motion; a motion extender for extending an effect of a motion to adjacent pixels; and an edge detector for detecting an edge direction for a pixel to be interpolated in a current field, detecting a characteristic of a local correlation in the vertical direction, and providing additional information necessary for a detection of intra-field motion information and a calculation of intra-field motion extent.